Transformer or the like



May-31, 1932- L. c. NICHOLS 1,860,511

TRANSFORMER OR THE LIKE Original Filed Nov. 19, 1924 /z I [,l

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Patented May 31, 1932 UNITED STATES PATENT QFFICE LOUIS C. NICHOLS, OF WAUWATOSA, WISCONSIN, ASSIGNOR TO ALLIS-Cl-IALMERS MANU- FACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELANARE TRANSFORMER OR THE LIKE Original application filed November 19, 1924, Serial No. 750,781. Divided and this application filed March This invention relates to enclosed electrical apparatus adapted to be filled with oil or other insulating fluid. The term oil is used hereinafter, for the sake of brevity, to connote any suitable insulating fluid. One of its uses is in connection with oil-filled transformers and it will be more particularly described in that relation.

Inasmuch as transformers are often located out of doors, and in certain places are therefore exposed to low temperatures, it may occur, especially if the transformer is out of service for a time, or the load is small, that the oil in the expansion chamber or the pipe connecting it to the transformer gets substantially solid and when the transformer is again put in service high pressure may develop within the casing as the solidified oil is difficult to move through a small opening. It is accordingly an object of the invention to provide means whereby these undesirable effects may be avoided. It is a more specific object to provide means whereby even though the load on a transformer is small the passage between the transformer casing and the expansion chamber will be kept open, or if the oil does solidify, high pressures may be relieved and their destructive effects avoided.

ther objects will appear hereinafter as the description of the invention proceeds.

The novel features of the invention will appear from this specification and the accompanying drawings forming a part thereof and disclosing several embodiments of said invention and all these novel features are intended to be pointed out in the claims.

This application is a division of application Ser. No. 7 50,781, filed November 19, 1924, and which has matured into Patent No. 1,793,820, February 24, 1931.

In the drawings, in which corresponding parts have been given the same reference characters Fig. 1 is a fragmentary side elevation of a transformer in which the invention has been embodied, parts being in section.

Fig. 2 is a similar view of a modification.

Referring to Fig. 1, a transformer casing 1 adapted to contain the core, windings and other transformer elements proper, is here Serial No. 350,526.

shown as provided with low tension bushings 2 and one or more high tension bushings 3. An expansion tank or chamber (usually of cylindrical form but not necessarily), is in communication with the top of tank 1 through a large conduit. This conduit is here shown as comprising a pipe section 5, usually welded to the lid of the tank 1, and a pipe section 6 usually welded to the expansion tank 4. The pipe sections 5, 6 may be fastened together by bolts not shown, passing through a pair of flanges 7, 8 associated with pipe sections 5, 6 respectively. In Fig. 1 the pipe section 6 is shown as extending through and into the expansion tank 4, the lower edge of the end of pipe 6 being preferably above the bottom of tank 4 so that any water which may collect in said tank will not be drawn into the transformer tank. The upper edge of the end of pipe 6 within chamber 4 is here shown as below the cold level of the oil in the chamber 4. A pipe 9 communicating with chamber 4 and usually welded thereto is disposed so as to be in line with the pipe 6. The pipe 9 is provided witha closure or valve 10 which may be swingable about a pivot 11 mounted on a suitable bracket in turn mounted on the pipe 9. The valve 10 may be held closed by means of a breakable bolt 12. Any other suitable form of openable closure may be substituted for the valve 10.

In order to prevent the circulation of hot oil from the transformer tank through the pipes 5, 6 directly to the level of oil in the expansion chamber 4, the end of the pipe 6 within chamber 4 is provided with a suitable closure means which nevertheless permits expansion of the oil in the tank and consequent flow of oil into the expansion tank, as distinguished from a thernio-syphon flow. This means is here shown as a valve 13 which may be pivoted at a point 14. The valve 13 is itself here shown as provided with an opening 15 which may be held closed by means of a valve 16 pivoted to the valve 13 at the point 17. A weight 18 is here shown as associated with the valve 16 and so disposed with respect to the pivot 17 that the valve 16 is normally held closed by the action of gravity. Other suitable means may clearly be munication, if desired.

.ify in cold weather.

substituted. The chamber 4 is provided with a vent pipe 19 of any suitable form thereby placing the air above the oil in chamber 4 in communication with the atmosphere. The bottom of chamber 4 is provided with a drain cook 20 through which water or sediment may be drained from the bottom of said chamber.

The operation of the apparatus shown in Fig. 1 is: as follows. As the oil in trans former 1 heats up it gradually expands and some of this oil is expanded out through pipes 5, 6 thereby lifting the valve 13 and permitting this oil to flow into expansion chamber 4. Air is of course then expelled through pipe 19. When the oil in tank 1 cools it contracts thereby opening valve 16 and drawing oil from the expansion chamber 4. When no expansion or contraction of the oil in tank 1 is taking place communication between expansion chamber 4 and tank 1 is cut off by the valves 13, 16, and as hereinbefore stated circulation of hot oil from tank 1 to the surface of the oil in chamber 4 is prevented. This circulation of oil, however, keeps the oil below the valve 13 in a fluid condition so that the oil at the point of communication between chamber 4 and the end of pipe 6 within said chamber will not solid If an explosion occurs within tank 1 the pipes 5, 6 constitute a straight line exit from tankl and inasmuch as pipe 9 is in line with pipe 6 any oil or gas shot through pipe 6 will readily leave by way of pipe 9 after the valve 10, due to the high pressures, has opened.

Referring now to Fig. 2 the expansion chamber 4 is here shown in communication with the tank 1 through a pipe 21, corresponding in certain respects to the pipe 6 of Fig. 1. The pipe 21 communicates indirectly with the chamber 4 at its upper edge, which is here shown as cut off on the line 23 so as to afford a somewhat larger passage of com- Tn line with pipe 21 is a pipe 22 extendin into the chamber 4 from the opposite direction of pipe 21. pipe 22 is here shown as of larger diameter than pipe 21 and the upper edge 25 thereof in contact with the inside of chamber 4 preferably below the cold oil level or the level of the oil when the apparatus is first filled. The lower edge 26 of pipe 22 is preferably above the bottom of chamber 4 in order that any water or sediment which may be on the bottom of said chamber will not be drawn upwards through the passage between pipes 21. and 22 when the oil in tank 1 is contracted. The relation of the edges 25 and 26 with respect to the chamber 4 may be attained by suitably cutting the end of pipe 22 or shaping it in the desired manner, or the chamber 4 may be suitably shaped. The pipe 22 is provided with an openable closure 10 as de scribed in connection with Fig. 1. It will be noted that in view of the fact that the pipe The 22 extends down over pipe 21 that an oil seal is formed for the air in pipe 22 above the oil level. The oil level shown in Fig. 5 is preferably the cold level. When the oil in tank 1 heats up oil will flow upwardly through pipe 21 and discharge indirectly into chamber 4 through the space between pipes 22 and 21. As tl e oil again contracts it will first reach a level at the lowest edge 24 of pipe 21, after which further contraction of theoil will produce a partial vacuum in the pipe 22 thereb drawin oil up between pipes 22 and 21. Ft is evident that circulation of oil from tank 1 through pipe 21 to the major part of the oil level in chamber 4 is prevented, the circulation being only to that portion of the level exposed in pipe 21 to theair in pipe22. This pipe as is evident is not normally in communication with the atmosphere.

It should be understood that it is not desired to limit the invention to the exact details of construction shown and described, for obvious modifications may occur to a person skilled in the art.

It is claimed and desired to secure by Let ters Patent:

1. The combination with a transformer tank, an oil expansion tank, a pipe of large diameter extending from the top of said transformer tank into said expansion tank and a valve in said expansion tank normally closing the end of said pipe and operating upon a decrease in pressure in said transformer tank to permit oil to enter said transformer tank from said expansion tank.

2. A transformer tank, an oil expansion tank, a pipe of large diameter connectingsaid tanks, and valve means interrupting the circulation to reduce the transfer of heat between the oil in said pipeand the body of oil in said expansion tank, said valve means being constructed to provide a passage for a flow of oil between said tanks solely when pressure in one of said tanks is different from the pressure in the other of said tanks.

3. A transformer tank, an oil expansion tank, a pipe of large diameter extending from said transformer tank and being located partly in said expansion tank and means preventing the free passage of heated oil from said pipe into the body of oil in said expansion tank whereby a large body of heated oil is maintained in said pipe in said expansion tank, and said means being formed so as to permit the passage of oil from the body of oil in said expansion tank into said.

pipe on reduction of pressure in said pipe. 4. In combination, a casing for electrical. apparatus adapted to contain 011, an expansion chamber therefor, a pipe for placing said casing and chamber in communication with sa1d pipe terminating in sa1d chamber above the bottom of said chamber, 011 in said casing extending into sa1d pipe and chamber, heat- 1ng of the oil in sa1d casing causing circulation of heated oil into the portion of said pipe extending into said chamber, and means for preventing free interchange of said circulating oil and the body of oil in said chamher.

5. In combination, a casing for electrical apparatus adapted to contain oil, an expansion chamber therefor, a pipe affording communication between said casing and said chamber, extending into said chamber and terminating above the bottom thereof, and valve means normally closing the chamber terminus opening of said pipe.

6. In combination, a casing for electrical apparatus adapted to contain oil, an expansion chamber therefor, a pipe affording communication between said casing and said chamber, extending into said chamber above the bottom thereof, and means including a compound valve normally closing communication between said casing and chamber and permitting expansion of oil into said chamber and contraction of oil into said casing.

7. In combination, a casing for electrical apparatus adapted to contain oil, an expansion chamber therefor, a pipe affording communication between said casing and said chamber, a compound valve controlling said communication comprising a valve member having an opening, another valve member for normally closing said opening whereby said communication is closed except when said oil is expanding or contracting.

8. In combination, a casing for electrical apparatus adapted to contain oil, an expan sion chamber therefor, means including a pipe for placing said casing and chamber in communication having its lowest point of communication above the bottom of said chamber and a pressure responsive valve for said pipe disposed within the confines of said expansion chamber.

9. In combination, a casing for electrical apparatus adapted to contain oil, an expan sion chamber therefor, a pipe for placing said casing and chamber in communication with said pipe terminating in said chamber above the bottom of said chamber, oil in said casing extending into said pipe and chamber, heating of the oil in said casing causing circulation of heated oil into the portion of said pipe extending into said chamber, and means sealing the chamber terminus of said pipe responsive to a difference in pressure between said casing and expansion chamber to thereby prevent free interchange of said circulating oil and the body of oil in said chamber while permitting expansion of oil from said easing into said chamber.

10. A transformer tank, an oil expansion tank, means forming a passage of large diameter between the tanks, means normally closing the end of said passage nearest the expansion tank, means operating on decrease in pressure in the transformer tank to provide a wide opening at the said end of said passage whereby oil may flow freely from the expansion tank to the transformer tank, and means operating on increase in pressure in the transformer tank to provide a wide opening at the said end of said passage whereby oil may flow freely from the transformer tank to the expansion tank.

11. The combination of a transformer tank, an oil expansion tank, a single normally closed passage between the tanks, and means operating upon an increase or decrease in pressure in said transformer tank to establish free communication between said tanks.

12. The combination of a transformer tank, an expansion tank, a single pipe connecting the tanks and extending into said expansion tank, a valve normally closing communication between said pipe and said expansion tank and operating upon an increase in pressure in said transformer tank to open communication between said pipe and expansion tank, and a valve normally closing communication between said pipe and expansion tank and operating on decrease in pressure in said transformer tank to open communication between said expansion tank and transformer tank.

In testimony whereof, the signature of the inventor is affixed hereto.

LOUIS C. NICHOLS. 

